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United States Patent |
5,246,911
|
Murata
,   et al.
|
September 21, 1993
|
Thermal transfer recording sheet and ink composition for producing the
same
Abstract
A thermal transfer recording sheet comprising a substrate having thereon a
colorant layer, the colorant layer comprising a binder and a pyridone-type
azo dyestuff represented by the following general formula (I):
##STR1##
wherein R represents a hydrogen atom, an alkyl group having 2 or more
carbon atoms, a substituted alkyl group, a cycloalkyl group, an allyl
group, or a substituted or unsubstituted phenyl group is disclosed. A
thermal transfer recording ink composition for use in forming the colorant
layer on a substrate is also disclosed.
Inventors:
|
Murata; Yukichi (Kanagawa, JP);
Nakamura; Mio (Tokyo, JP);
Morishima; Takashi (Austin, TX)
|
Assignee:
|
Mitsubishi Kasei Corporation (Tokyo, JP)
|
Appl. No.:
|
981089 |
Filed:
|
November 24, 1992 |
Foreign Application Priority Data
Current U.S. Class: |
503/227; 428/480; 428/913; 428/914 |
Intern'l Class: |
B41M 005/035; B41M 005/38 |
Field of Search: |
8/471
428/195,211,335,336,480,913,914
503/227
|
References Cited
U.S. Patent Documents
4808568 | Feb., 1989 | Gregory et al. | 503/227.
|
Foreign Patent Documents |
323259 | May., 1989 | EP | 503/227.
|
Other References
Patent Abstracts of Japan, abstract of JP-A-60 27594.
Patent Abstracts of Japan, abstract of JP-A 63 39380.
|
Primary Examiner: Hess; B. Hamilton
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak & Seas
Parent Case Text
This is a continuation of Application No. 07/654,469 filed Feb. 13, 1991,
now U.S. Pat. No. 5,189,008.
Claims
What is claimed is:
1. A thermal transfer recording sheet comprising a substrate having thereon
a colorant layer, said colorant layer comprising a binder and a
pyridone-type azo dyestuff represented by the following general formula
(I):
##STR63##
wherein R represents an alkoxy group-substituted alkyl group.
2. A sheet as claimed in claim 1, wherein said binder is a water-soluble
resin selected from the group consisting of cellulose resins, acrylic
acid-based resins, polyvinyl alcohols, polyethylene oxides, and starches,
or an organic solvent-soluble resin selected from the group consisting of
acrylic resins, methacrylic resins, polystyrenes, polycarbonates,
polysulfones, AS resins, polyethersulfones, epoxy resins, polyvinyl
acetals, phenoxy resins, polyvinyl butyrals, polyesters, ethyl celluloses,
and acetyl celluloses.
3. A sheet as claimed in claim 1, wherein said substrate is a sheet of
paper selected from capacitor paper and glassine paper or a film of
heat-resistant plastics selected from the group consisting of polyesters,
polycarbonates, polyamides, polyimides, and polyaramids, and has a
thickness in the range of from 1 to 50 .mu.m.
4. A sheet as claimed in claim 3, wherein said substrate is a polyethylene
terephthalate film.
5. A sheet as claimed in claim 3, wherein said substrate has a
heat-resistant resin layer on the side thereof opposite to the colorant
layer.
Description
FIELD OF THE INVENTION
The present invention relates to a thermal transfer recording sheet for use
in thermal transfer recording, particularly in sublimation-type thermal
transfer recording, and to an ink composition for use in producing the
thermal transfer recording sheet.
BACKGROUND OF THE INVENTION
Conventionally, studies are being made of color recording techniques based
on electrophotographic printing, ink-jet printing, thermal transfer
printing, etc., for the purpose of applying such color recording
techniques to facsimile, copying machines, printers, or the like.
Among these recording techniques, the thermal transfer recording technique
is thought to be more advantageous than the others because the maintenance
and operation of the apparatus are easy and the apparatus and its
expendable supplies are inexpensive.
There are two systems in the thermal transfer recording: fusion-type
transfer in which a transfer recording sheet consisting of a base film and
formed thereon a thermally fusible ink layer is heated with a thermal head
to fuse the ink and transfer the fused ink to an image-receiving surface,
thereby recording an image on the receiving surface; and sublimation-type
transfer in which a transfer recording sheet consisting of a base film and
formed thereon a colorant layer containing a sublimable dyestuff is heated
with a thermal head to sublimate and/or heat-diffuse the dyestuff and
transfer the dyestuff from the transfer recording sheet to an
image-receiving surface, thereby recording an image on the receiving
surface. The sublimation-type transfer is particularly advantageous to
full-color recording over the fusion-type in that gradation recording is
easy since the transferred amount of the dyestuff can be controlled by
changing the energy fed to the thermal head.
In the thermal transfer recording of the sublimation type, sublimable
dyestuffs used in transfer recording sheets and in ink compositions for
producing transfer recording sheets greatly affect the speed of transfer
recording, the quality and storage stability of prints, etc. Therefore,
the sublimable dyestuffs are highly important and need to satisfy the
following requirements:
(1) the dyestuffs should readily sublimate and/or heat-diffuse under
operation conditions for the thermal head;
(2) they should not undergo thermal decomposition under operation
conditions for the thermal head;
(3) they should possess tints favorable for color reproduction;
(4) they should have high molecular absorption coefficients;
(5) they should be stable to heat, light, moisture, chemicals, etc.;
(6) they should be able to be easily synthesized;
(7) they should have good suitability for use in preparing inks; and
(8) they should have no health and safety problems.
However, a dyestuff which meets all the above requirements has not been
found so far. Yellow dyestuffs, in particular, have various defects and
satisfactory one has not yet been developed.
Conventionally known yellow dyestuffs having suitability to thermal
transfer recording of the sublimation type are disclosed, for example, in
JP-A-61-244595, JP-A-60-27594, and U.S. Pat. No. 4,808,568. (The term
"JP-A" as used herein means an "unexamined published Japanese patent
application".) These yellow dyestuffs are pyridone-type monoazo dyestuffs
having the same basic structure as that of the dyestuff employed in the
present invention. However, even the dyestuffs whose structural formulae
are specified in those references have had still insufficient
performances.
SUMMARY OF THE INVENTION
Under the above-stated circumstances, the present inventors have
investigated pyridone-type azo dyestuffs in greater detail. As a result,
it has been found that by introducing a fluorine atom into a pyridone-type
azo compound at the meta position of the benzene ring bonded to the azo
group, the resulting compound produces higher performance, particularly in
sensitivity and light resistance, than the conventional pyridone-type azo
dyestuffs. The present invention has been completed based on this finding.
Accordingly, an object of the present invention is to provide a thermal
transfer recording sheet employing a yellow dyestuff which satisfies all
of the above-listed requirements.
Another object of the present invention is to provide an ink composition
for use in manufacturing the thermal transfer recording sheet.
Other objects and effects of the present invention will be apparent from
the following description.
In one aspect of the present invention, a thermal transfer recording sheet
is provided which comprises a substrate having thereon a colorant layer,
the colorant layer comprising a binder and a pyridone-type azo dyestuff
represented by the following general formula (I):
##STR2##
wherein R represents a hydrogen atom, an alkyl group having 2 or more
carbon atoms, a substituted alkyl group, a cycloalkyl group, an allyl
group, or a substituted or unsubstituted phenyl group.
In another aspect of the present invention, an ink composition for use in
manufacturing the above thermal transfer recording sheet is provided which
ink composition comprises the pyridone-type azo dyestuff represented by
general formula (I), a binder resin, and a medium.
DETAILED DESCRIPTION OF THE INVENTION
The dyestuff employed in the present invention and represented by general
formula (I) given above is explained below referring to its examples.
Examples of the unsubstituted alkyl group represented by R in general
formula (I) include straight-chain or branched alkyl groups having 2 to 8
carbon atoms. Examples of the substituted alkyl group represented by R
include groups formed by substituting straight-chain or branched alkyl
groups having 1 to 8 carbon atoms. Specific examples thereof include
hydroxy-substituted alkyl groups such as 2-hydroxyethyl group,
3-hydroxypropyl group, 4-hydroxybutyl group, and 2-hydroxypropyl group;
carboxy-substituted alkyl groups such as carboxymethyl group,
2-carboxyethyl group, and 3-carboxypropyl group; cyano-substituted alkyl
groups such as 2-cyanoethyl group and cyanomethyl group; amino-substituted
alkyl groups such as 2-aminoethyl group; halogen-substituted alkyl groups
such as 2-chloroethyl group, 3-chloropropyl group, 2-chloropropyl group,
and 2,2,2-trifluoroethyl group; alkyl groups substituted with phenyl group
which may have a halogen atom, such as benzyl group, p-chlorobenzyl group,
and 2-phenylethyl group; alkoxy-substituted alkyl groups such as
2-methoxyethyl group, 2-ethoxyethyl group, 2-n-propoxyethyl group,
2-isopropoxyethyl group, 2-n-butoxyethyl group, 2-isobutoxyethyl group,
2-(2-ethylhexyloxy)ethyl group, 3-methoxypropyl group, 4-methoxybutyl
group, and 2-methoxypropyl group; alkoxyalkoxy-substituted alkyl groups
such as 2-(2-methoxyethoxy)ethyl group, 2-(2-ethoxyethoxy)ethyl group,
2-(2-n-propoxyethoxy)ethyl group, 2-(2-isopropoxyethoxy)ethyl group,
2-(2-n-butoxyethoxy)ethyl group, 2-(2-isobutoxyethoxy)ethyl group, and
2-(2-(2-ethylhexyloxy)ethoxy)ethyl group; alkenyloxyalkyl groups such as
allyloxyethyl group; aryloxyalkyl groups such as 2-phenoxyethyl group;
aralkyloxysubstituted alkyl groups such as 2-benzyloxyethyl group; alkyl
groups substituted with an acyloxy group which may be substituted with a
halogen atom, such as 2-acetyloxyethyl group, 2-propionyloxyethyl group,
2-n-butyryloxyethyl group, 2-isobutyryloxyethyl group, and
2-trifluoroacetyloxyethyl group; alkyl groups substituted with a
substituted or unsubstituted alkoxycarbonyl group, such as
methoxycarbonylmethyl group, ethoxycarbonylmethyl group,
n-propoxycarbonylmethyl group, isopropoxycarbonylmethyl group,
n-butoxycarbonylmethyl group, isobutoxycarbonylmethyl group,
2-ethylhexyloxycarbonylmethyl group, benzyloxycarbonylmethyl group,
furfuryloxycarbonylmethyl group, tetrahydrofurfuryloxycarbonylmethyl
group, 2-methoxycarbonylethyl group, 2-ethoxycarbonylethyl group,
2-n-propoxycarbonylethyl group, 2-isopropoxycarbonylethyl group,
2-n-butoxycarbonylethyl group, 2-isobutoxycarbonylethyl group,
2-(2-ethylhexyloxycarbonyl)ethyl group, 2-benzyloxycarbonylethyl group,
and 2-furfurylcarbonylethyl group; alkyl groups substituted with a
substituted or unsubstituted alkoxycarbonyloxy group, such as
2-methoxycarbonyloxyethyl group, 2-ethoxycarbonyloxyethyl group,
2-n-propoxycarbonyloxyethyl group, 2-isopropoxycarbonyloxyethyl group
2-n-butoxycarbonyloxyethyl group, 2-isobutoxycarbonyloxyethyl group,
2-(2-ethylhexyloxycarbonyloxy)ethyl group, 2-benzyloxycarbonyloxyethyl
group, and 2-furfuryloxycarbonyloxyethyl group; heterocyclic
ring-substituted alkyl groups such as furfuryl group and
tetrahydrofurfuryl group; and the like.
Examples of the cycloalkyl group represented by R include cyclopentyl
group, cyclohexyl group, and the like.
Examples of the substituted phenyl group represented by R include phenyl
group substituted with a straight-chain or branched alkyl group having 1
to 8 carbon atoms; phenyl group substituted with a straight-chain or
branched alkoxyl group having 1 to 4 carbon atoms; phenyl group
substituted with a halogen atom such as fluorine atom, chlorine atom, or
bromine atom; and phenyl group substituted with nitro group, cyano group,
trifluoromethyl group, or the like.
Particularly preferred examples of the group of R include straight-chain or
branched alkyl groups having 2 to 8 carbon atoms, alkoxyalkyl groups
having 3 to 8 carbon atoms, benzyl group, 2-phenylethyl group, allyl
group, dialkylaminoalkyl groups having 4 to 10 carbon atoms, and the like.
Specific examples of the dyestuff represented by general formula (I)
described above are listed in the following Table 1.
TABLE 1
______________________________________
##STR3##
No. R
______________________________________
1 H
2 C.sub.4 H.sub.9 (n)
3 C.sub.6 H.sub.13 (n)
4 C.sub.8 H.sub.17 (n)
5 C.sub.4 H.sub.9 (i)
6
##STR4##
7 CH.sub.2 CHCH.sub.2
8 (CH.sub.2).sub.2 OH
9 (CH.sub.2).sub.3 OH
10 (CH.sub.2).sub.4 OH
11
##STR5##
12 CH.sub.2 COOH
13 (CH.sub.2).sub.2 COOH
14 (CH.sub.2 ) .sub.3COOH
15 (CH.sub.2).sub.2 CN
16 CH.sub.2 CN
17 (CH.sub.2 ) .sub.2NH.sub.2
18 (CH.sub.2).sub.2 Cl
19 (CH.sub.2).sub.3 Cl
20
##STR6##
21 CH.sub.2 CF.sub.3
22
##STR7##
23
##STR8##
24
##STR9##
25 (CH.sub.2).sub.2 OCH.sub.3
26 (CH.sub.2).sub.2 OC.sub.3 H.sub.7 (n)
27 (CH.sub.2).sub.2 OC.sub.4 H.sub.9 (n)
28 (CH.sub.2).sub.2 OC.sub.4 H.sub.9 (i)
29
##STR10##
30 (CH.sub.2).sub.2 OCH.sub.3
31 (CH.sub.2).sub.3 OC.sub.3 H.sub.7 (i)
32 (CH.sub.2 ) .sub.3OC.sub.4 H.sub.9 (n)
33 (CH.sub.2).sub.2 OCH.sub.3
34
##STR11##
35 [(CH.sub.2 ).sub.2 O] .sub.2CH.sub.3
36 [(CH.sub.2).sub.2 O] .sub.2CH.sub.2 CH.sub.3
37 [(CH.sub.2).sub.2 O] .sub.2C.sub.2 H.sub.7 (n)
38 [(CH.sub.2).sub.2 O] .sub.2C.sub.3 H.sub.7 (i)
39 [(CH.sub.2).sub.2 O] .sub.2C.sub.4 H.sub.9 (n)
40 [(CH.sub.2).sub.2 O] .sub.2C.sub.4 H.sub.9 (i)
41
##STR12##
42 (CH.sub.2).sub.2 OCH.sub.2 CHCH.sub.2
43
##STR13##
44
##STR14##
45 (CH.sub.2).sub.2 OCOCH.sub.3
46 (CH.sub.2).sub.2 O COC.sub.3 H.sub.7 (n)
47 (CH.sub.2).sub.2 OCOC.sub.4 H.sub.9 (n)
48 (CH.sub.2).sub.2 O COC.sub.4 H.sub.9 (i)
49 (CH.sub.2).sub.2 OCOCF.sub.3
50 CH.sub.2 COOCH.sub.3
51 CH.sub.2 COOCH.sub.2 CH.sub.3
52 CH.sub.2 COOC.sub.3 H.sub.7 (n)
53 CH.sub.2 COOC.sub.3 H.sub.7 (i)
54 CH.sub.2 COOC.sub.4 H.sub.9 (n)
55 CH.sub.2 COOC.sub.4 H.sub.9 (i)
56
##STR15##
57
##STR16##
58
##STR17##
59
##STR18##
60 (CH.sub.2).sub.2 COOCH.sub.3
61 (CH.sub.2).sub.2 COOCH.sub.2 CH.sub.3
62 (CH.sub.2).sub.2 COOC.sub.3 H.sub.7 (n)
63 (CH.sub.2).sub.2 COOC.sub.3 H.sub.7 (i)
64 (CH.sub.2).sub.2 COOC.sub.4 H.sub.9 (n)
65 (CH.sub.2).sub.2 COOC.sub.4 H.sub.9 (i)
66
##STR19##
67
##STR20##
68
##STR21##
69 (CH.sub.2).sub.2 OCOOCH.sub.3
70 (CH.sub.2).sub.2 OCOOC.sub.2 H.sub.5
71 (CH.sub.2).sub.2 OCOOC.sub.3 H.sub.7 (n)
72 (CH.sub.2).sub.2 OCOOC.sub.3 H.sub.7 (i)
73 (CH.sub.2).sub.2 OCOOC.sub.4 H.sub.9 (n)
74 (CH.sub.2).sub.2 OCOOC.sub.4 H.sub.9 (i)
75
##STR22##
76
##STR23##
77
##STR24##
78
##STR25##
79
##STR26##
80
##STR27##
81
##STR28##
82
##STR29##
83
##STR30##
84
##STR31##
85
##STR32##
86
##STR33##
87
##STR34##
88
##STR35##
89
##STR36##
90
##STR37##
91
##STR38##
92
##STR39##
93
##STR40##
94
##STR41##
95
##STR42##
96
##STR43##
97
##STR44##
98
##STR45##
99
##STR46##
100
##STR47##
101
##STR48##
102
##STR49##
103
##STR50##
104
##STR51##
105
##STR52##
106 C.sub.2 H.sub.5
______________________________________
The pyridone-type azo dyestuff of general formula (I) to be employed in the
present invention can be produced according to conventionally known
methods. For example, it may be obtained by diazotizing m-fluoroaniline in
an ordinary manner and then coupling the diazotization product with a
pyridone derivative of the following general formula (II):
##STR53##
(wherein R has the same meaning as in general formula (I) given
hereinabove) in an ordinary manner.
In manufacturing the thermal transfer recording sheet of the present
invention, methods for forming the colorant layer containing the dyestuff
of general formula (I) are not particularly limited. Generally, the
dyestuff is dissolved or finely dispersed, along with a binder, in a
medium to prepare an ink, which is then applied on a substrate and dried,
thereby forming a colorant layer on the substrate.
The binder for use in ink preparation should have good heat resistance for
the purpose of preventing the heat fusion-adhesion of the binder onto an
image-receiving surface at the time of transfer recording. Especially
preferred binders are ones having softening points and/or heat deformation
temperatures of 100.degree. C. or more.
Examples of the binder include water-soluble resins such as cellulose
resins, acrylic acid-based resins, starches, polyvinyl alcohols, and
polyethylene oxides, organic solvent-soluble resins such as acrylic
resins, methacrylic resins, polystyrenes, polycarbonates, polysulfones, AS
resins, polyethersulfones, epoxy resins, polyvinyl acetals, phenoxy
resins, polyvinyl butyrals, polyesters, ethyl celluloses, and acetyl
celluloses, and the like.
According to the medium to be used for ink preparation, a binder soluble or
uniformly dispersible into the medium may be suitably selected from the
above resins.
The amount of such a binder resin used is generally in the range of from 1
to 40% by weight, preferably from 5 to 30% by weight, based on the total
amount of the ink composition.
Besides water, examples of the medium for use in the ink preparation are
organic solvents which include alcohols such as methyl alcohol, n-propyl
alcohol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol,
Cellosolves such as methyl Cellosolve, ethyl Cellosolve and butyl
Cellosolve, aromatics such as toluene, xylene, and chlorobenzene, esters
such as ethyl acetate and butyl acetate, ketones such as acetone, methyl
ethyl ketone, methyl isobutyl ketone, and cyclohexanone,
chlorine-containing solvents such as methylene chloride, chloroform, and
trichloroethylene, ethers such as tetrahydrofuran and dioxane,
N,N-dimethylformamide, N-methylpyrrolidone, and the like. These may be
used alone or as a mixture of two or more thereof.
In addition to the ingredients described above, organic or inorganic
non-sublimable fine particles, a dispersant, an anti-static agent, an
anti-blocking agent, an anti-foaming agent, an antioxidant, a viscosity
modifier, a release agent, and the like may be incorporated into the ink
if required and necessary.
Preferred examples of the substrate on which the ink is to be applied for
preparing the thermal transfer recording sheet include a sheet of paper
such as capacitor paper, glassine paper, or the like, and a film of
heat-resistant plastics such as polyesters, polycarbonates, polyamides,
polyimides, polyaramids, or the like. The thickness of such a substrate
may be in the range of from 1 to 50 .mu.m.
Of the above substrates, a polyethylene terephthalate film is particularly
advantageous because of its high mechanical strength, good solvent
resistance, low cost, etc. In some cases, however, the polyethylene
terephthalate film is not always satisfactory in heat resistance,
resulting in insufficient running of the thermal head. Therefore, a
heat-resistant resin layer containing a surface-active agent, lubricating
heat-resistant particles, etc. may be provided on the side opposite to the
colorant layer, thus providing improved thermal head-running properties.
Coating of the ink on the substrate can be accomplished by use of a
reverse-roll coater, a gravure coater, a rod coater, an air-doctor coater,
or the like. The coating may be performed so as to give an ink coating
layer thickness in the range of from 0.1 to 5 .mu.m on a dry basis.
(Reference may be made to Yuji Harasaki, Coating Techniques, published in
1979 by Maki Shoten, Japan.)
On the other hand, the ink composition for use in producing the thermal
transfer recording sheet, which ink composition is provided according to
another aspect of the present invention comprises a pyridone-type azo
dyestuff represented by the above-described general formula (I), a binder
resin, and a medium that may be an organic solvent and/or water.
The pyridone-type azo dyestuff is as described in detail hereinabove.
The binder to be used is suitably selected from the above-mentioned resins
which are soluble in water or organic solvents, according to the medium to
be used.
Of the above-mentioned resins, those having heat deformation temperatures
and/or softening points of 100.degree. C. or more are particularly
preferred. As the organic solvent, any of the above-mentioned solvents may
be used. In addition to these, non-sublimable fine particles and additives
such as a dispersant, antistatic agent, anti-blocking agent, anti-foaming
agent, antioxidant, viscosity modifier, and release agent may be used as
mentioned hereinabove.
The amount of the dyestuff of general formula (I) contained in the ink
composition of the present invention is generally from 1 to 30% by weight,
preferably from 3 to 20% by weight, based on the total amount of the ink
composition.
The ink composition of the present invention may be prepared as follows. In
one method, a liquid mixture composed of the dyestuff, a medium, and a
resin is placed in a proper vessel equipped with a stirrer and the
dyestuff is dissolved in the medium, with heating if required and with
addition of additives etc. if necessary, thereby to prepare an ink
composition. Alternatively, the liquid mixture may be treated with a paint
conditioner, ball mill, sand grinding mill, or the like to uniformly
disperse the dyestuff into the medium, with addition of additives etc. if
necessary, thereby to prepare an ink composition.
Because the pyridone-type azo dyestuff of general formula (I) which is
employed in the thermal transfer recording sheet of the present invention
possesses a vivid yellow color, it is suited for use in combining it with
suitable cyan color dyestuffs and suitable magenta color dyestuffs to
attain full-color recording with good color reproduction. Further, because
the dyestuff of general formula (I) readily sublimates and/or
heat-diffuses and has a high molecular absorption coefficient, recorded
images having high color densities can be obtained at a high speed without
a heavy load on the thermal head. The dyestuff also has good stability to
heat, light, moisture, chemicals, etc. and, hence, it never undergoes
thermal decomposition during transfer recording and the permanence
properties of the resulting recorded images are also good, particularly in
light resistance. In addition, since the dyestuff of general formula (I)
has good solubility in organic solvents and good dispersibility into
water, it is easy to prepare an ink composition in which the dyestuff has
been uniformly dissolved or dispersed at a high concentration, and by use
of such an ink composition, a thermal transfer recording sheet having a
colorant coating layer in which the dyestuff is distributed uniformly at a
high concentration can be obtained. Therefore, by use of such a thermal
transfer recording sheet, printed images having good homogeneity and color
density can be obtained.
In practicing transfer recording using the thermal transfer recording sheet
of the present invention, infrared rays, laser light, etc. as well as a
thermal head may be utilized as a heating means.
It is also possible to coat the ink composition of the present invention on
a film that is heated by application of electric current and to use the
resulting sheet as an electrically-heated thermal transfer recording
sheet.
The present invention will be explained below in more detail by reference
to the following examples, which should not be construed to be limiting
the scope of the invention. In these examples, all parts are by weight.
EXAMPLE 1
______________________________________
(a) Preparation of Ink
______________________________________
Dyestuff No. 3 in Table 1
5 g
Polysulfone resin* 10 g
Chlorobenzene 100 g
Total 115 g
______________________________________
*trade name, "Udel P1700"; manufactured by Nissan Chemical Industries,
Ltd., Japan; heatdeformation temperature (ASTM D648) 175.degree. C.
A mixture having the above composition was treated with a paint conditioner
for 10 minutes, thereby preparing an ink.
(b) Preparation of Transfer Recording Sheet
The above-obtained ink was coated with a wire bar on a polyethylene
terephthalate film (6 .mu.m thick) whose back side had undergone treatment
for imparting heat resistance and lubricating properties. The coating was
then dried (coating layer dry thickness, about 1 .mu.m) to obtain a
transfer recording sheet. The above treatment for imparting heat
resistance and lubricating properties to the polyethylene terephthalate
film was conducted by coating the film with a fluid consisting of 8 parts
of a polycarbonate resin having the recurring unit of the formula
##STR54##
1 part of a phosphoric ester-type surfactant (trade name, "Plysurf
A-208B"; manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Japan), and 91
parts of toluene, and drying the coating (coating layer dry thickness,
about 0.5 .mu.m).
(c) Preparation of Image-Receiving Sheet
A composition consisting of 10 parts of a saturated polyester resin (trade
name, "TP-220"; manufactured by Nihon Gosei Co., Ltd., Japan), 0.5 part of
an amino-modified silicone (trade name, "KF 393"; manufactured by
Shin-Etsu Chemical Co., Ltd., Japan), 15 parts of methyl ethyl ketone, and
15 parts of xylene was coated on a synthetic paper (trade name, "Yupo FPG
150"; manufactured by Oji-Yuka Co., Ltd., Japan) with a wire bar, and then
dried (coating layer dry thickness, about 5 .mu.m). The coated synthetic
paper was further heat-treated in an oven at 100.degree. C. for 30 minutes
to prepare an image-receiving sheet.
(d) Transfer Recording
The transfer recording sheet prepared in (b) above was superimposed on the
image-receiving sheet in such a manner that the ink coating side of the
transfer recording sheet was in contact with the receiving sheet, and
recording was conducted by use of a thermal head under the conditions
shown below. As a result, a recorded image which was of a vivid yellow
color and had a uniform color density as shown in Table 3 could be
obtained.
______________________________________
Recording Conditions
______________________________________
Lineal density for main scanning
8 dots/mm
and sub-scanning:
Recording power: 0.25 W/dot
Heating time for head: 10 msec
______________________________________
Color density was measured with densitometer TR-927 manufactured by Macbeth
Corporation, U.S.A.
The light resistance of the recorded image obtained was examined by means
of a carbon arc fadeometer (manufactured by Suga Testing Machine Co.,
Ltd., Japan) at a black panel temperature of 63.degree..+-.2.degree. C.
The degree of discoloration through a 40-hour irradiation in the light
resistance test was shown in Table 3 in terms of .sup..increment. E.sup.*
value. Further, the transfer recording sheet and the print obtained were
found to be stable to heat and moisture and show good storage stability in
the dark.
The dyestuff used in this example had been synthesized by diazotizing
m-fluoroaniline in an ordinary way and coupling the diazotization product
with N-(n-hexyl)-3-cyano-4-methyl-6-hydroxy-2-pyridone in water medium.
Its maximum absorption wavelength in acetone was as shown in Table 3 and
its melting point was 156.9.degree.-158.8.degree. C.
EXAMPLES 2 TO 11
Inks and transfer recording sheets were prepared and transfer recording was
conducted in the same manner as in Example 1 except that in place of the
dyestuff used in Example 1, the dyestuffs shown in Table 3 were used. As a
result, recorded images which were of a vivid yellow color and
respectively had color densities shown in Table 3 could be obtained, and
the light resistance of each recorded image was good as shown in Table 3.
COMPARATIVE EXAMPLES 1 TO 13
Inks and transfer recording sheets were prepared and transfer recording and
a light resistance test were conducted in the same manner as in Example 1
except that the dyestuffs shown in Table 2 given below were used in place
of the dyestuff used in Example 1. The results obtained are summarized in
Table 3.
TABLE 2
______________________________________
(Dyestuffs used in Comparative Examples)
##STR55##
Example No.Comparative
##STR56## R
______________________________________
1*
##STR57## C.sub.4 H.sub.9 (n)
2 " C.sub.4 H.sub.9 (i)
3 " C.sub.8 H.sub.17 (n)
4* " C.sub.2 H.sub.4 OCH.sub.3
5 " CH.sub.2 CHCH.sub.2
6*
##STR58## CH.sub.3
7 " C.sub.4 H.sub.9 (i)
8**
##STR59## C.sub.4 H.sub.9 (n)
9 " C.sub.4 H.sub.9 (i)
10**
##STR60## C.sub.4 H.sub.9 (n)
11 " C.sub.4 H.sub.9 (i)
12
##STR61## C.sub.4 H.sub.9 (i)
13
##STR62## CH.sub.3
______________________________________
Note:
*Dyestuffs described in JPA-60-27594
**Dyestuffs described in JPA-62-290583
TABLE 3
______________________________________
Maximum
absorption
wavelength*
Color Light
Dye No.
(nm) density resistance(.DELTA.E*)
______________________________________
Example 1
3 426 2.02 3.21
Example 2
2 426 2.05 3.15
Example 3
6 427 1.95 3.86
Example 4
31 426 1.96 3.92
Example 5
32 426 1.99 3.95
Example 6
4 426 2.01 3.90
Example 7
7 426 2.12 4.10
Example 8
22 426 1.90 3.81
Example 9
24 426 1.95 3.51
Example 10
79 426 1.98 3.85
Example 11
106 426 1.72 2.30
Comparative
-- 431 1.75 8.12
Example 1
Comparative
-- 432 1.55 2.16
Example 2
Comparative
-- 433 1.78 16.65
Example 3
Comparative
-- 434 1.58 1.68
Example 4
Comparative
-- 434 1.92 15.41
Example 5
Comparative
-- 428 1.25 9.15
Example 6
Comparative
-- 428 1.58 5.18
Example 7
Comparative
-- 430 1.65 12.55
Example 8
Comparative
-- 430 1.33 12.89
Example 9
Comparative
-- 432 1.90 8.64
Example 10
Comparative
-- 432 2.02 7.67
Example 11
Comparative
-- 421 1.19 1.82
Example 12
Comparative
-- 426 1.45 3.85
Example 13
______________________________________
*Measured in acetone
EXAMPLE 11
A transfer recording sheet was prepared and transfer recording was
conducted in the same manner as in Example 1 except that an ink prepared
according to the following formulation was used in place of the ink used
in Example 1. As a result, a recording image which was of a vivid yellow
color and had a uniform color density could be obtained. Further, the
recorded image was subjected to a light resistance test and the transfer
recording sheet and recorded image were subjected to a storage stability
test in the dark. As a result, good results were obtained in each test.
______________________________________
Preparation of Ink
______________________________________
Same dyestuff as that in Example 1
5 g
(dyestuff No. 3 in Table 1)
AS resin** 10 g
Toluene 90 g
Cyclohexanone 10 g
Total 115 g
______________________________________
**AS resin: trade name, "Denka ASS"; manufactured by Denki Kagaku Kogyo
K.K., Japan; Vicat softening point (JIS K6870) 105.degree. C.
While the invention has been described in detail and with reference to
specific embodiments thereof, it will be apparent to one skilled in the
art that various changes and modifications can be made therein without
departing from the spirit and scope thereof.
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